A first experience of fire might be described as follows:
Interaction with fire > Feeling + ensuing perception of this feeling [cittasaṅkhāra] > Thought (vitakka) of “?” + concretism (vicara) [vacīsaṅkhāra] > Word “Fire”.
The thought “?”, cannot be conceived apart from its form and heat (concretism).
Then , and only then, the thought “?” becomes the word “Fire”.
Concretism is the representation of an abstract thought, in concrete terms.
Representation should be considered as “concretism” - as a lexical more than a grammatical process (which will develop later as syntax/expression); as representing an abstract idea into a concrete term; as an attempt to embody a thought about a perceived feeling.
As far as Jhanas are concerned with vitakka/vicāra, what has to be abandoned in the first jhana is the word “fire” (speech). Then what has to be abandoned in the second jhana is the “mental materiality” of the fire (its form and heat); and the “thought” of it, that is seed.
Note:
“Concretism” (representation) would be more in line with such expressions like:
kshatryas’, brahmins’, householders’ representations are wisdom (paññūpavicārā); woman’s representation is adornment (alaṅkārūpavicārā); robbers’ representation is seizing (gahanūpavicārā) in AN 6.52 (EA 37.8, MA 149).
And Thanissaro’s:
Having first directed one’s thoughts and made an evaluation, one then breaks out into speech.
would become:_
Having thought and made a concretism, (a representation of that thought in concrete terms,) one then breaks out into a word.
Pubbe kho, gahapati, vitakketvā vicāretvā pacchā vācaṃ bhindati.
This article by Hirtle might be of interest.
Metta